The present inventors have recognized that industrial processes can benefit from monitoring of a physical property of a sample of substance being processed. For example, Gipsy Tabilo-Munizaga et al., “Rheology for the Food Industry,” J. Food Eng'g. 67 (2005) 147-156, which is incorporated by reference herein in its entirety, discusses rheological measurements for intermediate products during manufacturing and for finished foods. This discussion pertains to large-strain testing that involves deforming a sample to the point of permanent structural change, and small-strain testing that involves less deformation. The commercial rheometers described in Tabilo-Munizaga et al. appear to require insertion of a motor-driven rotor into the substance being processed.
Walker et al. U.S. Patent Application Publication US 2005/0148899 A1, entitled METHOD AND APPARATUS OF CLOT FORMATION, filed on Oct. 22, 2004 and published on Jul. 7, 2005, which is incorporated herein by reference in its entirety, discusses characterizing changes in at least on physical property of soft tissue. Acoustic pulses induce physical displacement of the tissue. Reflected waves are measured to estimate at least one characteristic of the physical displacement induced thereby, such as over time. Physical displacement of blood is measured to estimate at least one characteristic of the physical displacement induced thereby.
Walker et al. U.S. Pat. No. 6,039,691, entitled KINETIC ACOUSTIC OCULAR EXAMINATION APPARATUS AND METHOD, filed on May 29, 1998, and issued on Mar. 21, 2000, which is incorporated herein by reference in its entirety, discusses using ultrasound echo such as to examine the properties of a subject's vitreous body and thus to evaluate or diagnose ocular disorders, such as vitreous traction.
Gallippi et al. U.S. Patent Application Publication US 2010/0138163 A1, entitled METHODS, SYSTEMS, AND COMPUTER READABLE MEDIA FOR MONITORED APPLICATION OF MECHANICAL FORCE TO SAMPLES USING ACOUSTIC ENERGY AND MECHANICAL PARAMETER VALUE EXTRACTION USING MECHANICAL RESPONSE MODELS, filed on Oct. 18, 2009 and published on Jun. 10, 2010, includes a method for determining mechanical property parameters of a sample. Acoustic energy is used to apply a mechanical force to the sample. A measured response or recovery response can be used to determine a value for a first mechanical property parameter of the sample.